How to Troubleshoot the Control Box on a Deep Well Pump

Won’t Start or Intermittent Start

• 1

  Turn off your well pump’s power and unplug it from the receptacle. Failure to do so can cause serious injury while troubleshooting.

• 2

  Set your multimeter to read voltage above what your control box’s wiring diagram states is the maximum voltage. Pump control box voltages are typically 115 for each hot lead, so set the multimeter to read 150 volts.

• 3

  Disconnect the wiring to the control box terminals and place your multimeter probes on each terminal. You may need your Phillips screwdriver to do this. There should be terminals for black, yellow or red leads going from the motor to the control box.

• 4

  Verify that the leads were installed in the correct terminals if the voltage readings are incorrect by more than 10 percent according to your wiring diagram. If they are installed correctly, contact your power company to ensure your home’s power source is distributing the correct voltage to the pump receptacle.

Blown Fuses On Start

• 5

  Locate the fuses and compare the sizes to your wiring diagram’s fuse requirements. Do the same for the wiring size. Replace the fuses or wires if they are the incorrect sizes.

• 6

  Inspect the lead connecting points at both the control box terminal and the motor. Ensure they are secure or free of damage, such as exposed wiring that can cause arcing.

• 7

  Disconnect the capacitor’s wires. Place a screwdriver on top of the capacitor to discharge any static electricity.

• 8

  Set your multimeter to read ohms and place the probes on the capacitor’s terminals. If the multimeter does not indicate movement, the capacitor may be shorted out, requiring replacement.